1. Technical Field
The invention relates to a needle tip protector device which is mounted about a puncturing part of a puncturing needle after the puncturing needle has been removed from an indwelling needle.
2. Background of the Art
It is conventional to use an indwelling needle to supply a predetermined medicinal liquid and the like to the blood vessels of a patient to perform a medical procedure, such as artificial dialysis. The indwelling needle used in such a case includes a cannula for positioning a needle tip within the blood vessel of the patient and a body portion connected to the basal end portion of the cannula. In order to position the tip end of the cannula within a blood vessel, a puncturing needle is provided to pierce the body to facilitate smooth manipulation of the cannula into the blood vessel. When the manipulation described above is carried out, the puncturing needle is inserted into the indwelling needle such that the tip of the puncturing needle projects slightly from the tip end portion of the cannula. In that condition, the cannula together with the puncturing needle is inserted into the blood vessel. After the cannula is positioned within the blood vessel, the puncturing needle is pulled out of the indwelling needle and blood vessel and the rear end portion of the indwelling needle is connected to a tube member or the like for supplying the predetermined medicinal liquid to or from the blood vessel.
Such an indwelling needle set includes a needle tip protector for preventing the needle tip of the puncturing needle which is removed from the cannula from injuring the patient or the like (for example, see Patent Literature 1). The needle tip protector is formed by a cylinder comprising one end having an opening having a large inner diameter and the other end having an opening having a small inner diameter. The tip end portion of the puncturing needle to be protected by the needle tip protector is formed so as to have a size to allow passage of the puncturing needle through the large diameter opening of the needle tip protector but prevent passage of the puncturing needle through the small diameter opening of the needle tip protector. A rear portion of the puncturing needle is formed or is dimensioned to permit insertion through the small diameter opening. Therefore, when the puncturing needle is pulled rearwardly relative to the needle tip protector while the large diameter opening is opposed to the tip end portion of the puncturing needle and the rear portion of the puncturing needle is positioned though the small diameter opening, the needle tip protector will be engaged by the tip end portion of the puncturing needle such that the tip of the puncturing needle is covered by the needle tip protector.
Although, the conventional needle tip protector described above can not be removed from the tip end portion of the puncturing needle, the protector has a tendency to move towards the rear portion of the puncturing needle thus, exposing the tip end portion of the puncturing needle. Therefore, a needle tip protector capable of securely covering the tip end portion of the puncturing needle by fixing it to the tip end portion of the puncturing needle has been developed. One drawback of such a needle tip protector, however, is that the operationality of the needle tip protector may be negatively affected because the combination of the puncturing needle and the cannula and the like installed into the indwelling needle increases the length of the indwelling needle set.